Forest ThreatNet

Volume 2, Issue 1 - Winter 2009

Forest Fragmentation Creeps Across Scientific Boundaries

Riitters' research offers consistency to national studies

By Bridget O'Hara, NEMAC

Elbow room is what our forefathers were seeking when they colonized Turtle Island (the English translation of a Native American term for North America). As cities sprawl ever outward, smaller landowners have acquired more forest land for real estate development. New roads built to accommodate homes in these tranquil settings are impacting the distribution of forests and wildlife habitat in ways that researchers are struggling to understand.

EFETAC landscape ecologist Kurt Riitters' research has brought consistency to national forest fragmentation data.When EFETAC landscape ecologist Kurt Riitters became involved with Montreal Process Criteria and Indicator development (, forest fragmentation was identified as an important indicator of forest health. Unfortunately, the only available data to analyze the implications of fragmentation came from small localized studies. These datasets were extremely difficult to integrate, so Riitters worked to correct this problem by standardizing fragmentation metrics and producing nationally consistent data. This work has subsequently led to internationally consistent datasets that permit comparisons across nations and continents.

Above: EFETAC landscape ecologist Kurt Riitters' research has brought consistency to national forest fragmentation data.

Riitters combines satellite imagery and computer technology to classify and display the types, locations, and spatial scales of fragmentation down to 30-meter resolution, for any region of interest. Because spatial patterns of all land-cover types (not just forests) have implications for many resource concerns, the metrics created by Riitters are applicable to any cover type (rangeland, for example).

“If we adopt a top-down approach and start with a standardized set of metrics at a continental scale, it may be possible to actually use what has been learned by countless historical studies examining the details that are so dear to many areas of ecology,” says Riitters, who conducts research with EFETAC’s National Forest Health Monitoring research team in Research Triangle Park, NC. “After several decades of testing, the ‘up-scaling’ of those details has not proven tractable. As a result, very little has been said about the likely impacts of fragmentation at a national scale.” Basically, while the use of standardized fragmentation metrics by all ecologists cannot guarantee success when synthesizing results, it will make it more likely. Currently, many ecologists use different metrics, data, and/or scales of observations, which can create inconsistencies when attempting to synthesize results across species or geographic regions.

Standard metrics also create research opportunities that extend beyond biodiversity. Riitters adds, “Fragmentation, or more generally landscape pattern, is an indicator that is important for more reasons than just wildlife habitat and biodiversity, such as recreation and the spread of invasive species. For example, the common usage of a standard set of landscape pattern metrics will make it possible to talk about trade-offs between biodiversity and recreation.” He concludes, “While the advantages are clear, the adoption of a standard set of metrics does not come without a price. Many specialists will have to sacrifice a little disciplinary preference in order to achieve interdisciplinary discussion on common grounds.”



Google Earth Tool Targets Wide Audience


The extent that recreation, aesthetics, the spread of forest threats, and individual species are affected by forest fragmentation is not fully understood, but enough is known about the adverse effects of habitat loss and increased fragmentation to cause concern.

EFETAC landscape ecologist Kurt Riitters has collaborated with the European Commission Joint Research Center to develop an internet-based tool capable of displaying forest fragmentation data for any area of the United States, up to the continental scale. Riitters hopes this tool will be useful to landscape fragmentation analysts at all skill levels--from grade school students to professional researchers.

Google Earth logoGoogle Earth is required to view Riitters’ Landcover maps:

1) Go to

2) Under "Data and Tools," click on "Landcover Maps."

3) Choose links as appropriate.

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